阅读说明：本技术 一种带有储热的恒压型抽水压缩空气储能系统及运行方法 (Constant-pressure water-pumping compressed air energy storage system with heat storage function and operation method ) 是由 王焕然 陶飞跃 贺新 葛刚强 李丞宸 陈昊 李瑞雄 于 2020-11-24 设计创作，主要内容包括：本发明公开了一种带有储热的恒压型抽水压缩空气储能系统及运行方法,系统包括跨临界二氧化碳热机发电单元,中低温热源供应单元、用于储气和储热的双罐结构、用于连接发电机释能的膨胀单元,跨临界二氧化碳热机发电单元,用于吸收双罐结构提供的热量进行发电；双罐结构用于存储从中低温热源吸收的热量和换热器提供的热量以及被压缩的空气势能；自然冷量利用装置用于存储夜间自然冷量来冷却水轮机出口水流；中低温热源供应单元用于向跨临界二氧化碳热机发电单元提供热源；实现了采用水蒸气补压的恒压型抽水压缩空气储能系统的连续工作；在原有储存压力势能的基础上增加了对中低温热能的存储利用,提高储能密度；提高了系统的循环效率。(The invention discloses a constant-pressure water pumping compressed air energy storage system with heat storage and an operation method thereof, wherein the system comprises a transcritical carbon dioxide heat engine power generation unit, a medium-low temperature heat source supply unit, a double-tank structure for storing gas and heat, an expansion unit for connecting a generator to release energy, and the transcritical carbon dioxide heat engine power generation unit for absorbing heat provided by the double-tank structure to generate power; the double-tank structure is used for storing heat absorbed from a medium low-temperature heat source and heat provided by the heat exchanger and compressed air potential energy; the natural cold energy utilization device is used for storing natural cold energy at night to cool the water flow at the outlet of the water turbine; the medium-low temperature heat source supply unit is used for supplying a heat source to the transcritical carbon dioxide heat engine power generation unit; the continuous work of the constant-pressure water pumping compressed air energy storage system adopting water vapor pressure compensation is realized; the storage and utilization of medium-low temperature heat energy are increased on the basis of the original storage pressure potential energy, and the energy storage density is improved; the circulation efficiency of the system is improved.)

1. The constant-pressure water pumping compressed air energy storage system with the heat storage function is characterized by comprising a first high-pressure tank (1), a second high-pressure tank (2), a double-tank heat exchanger (15) and a transcritical carbon dioxide heat engine power generation unit, wherein water inlets and water outlets of the first high-pressure tank (1) and the second high-pressure tank (2) are respectively communicated with a water storage device (23), air inlets and air outlets of the first high-pressure tank (1) and the second high-pressure tank (2) are mutually communicated, the double-tank heat exchanger (15) is arranged on a path communicated with the air inlets and the air outlets of the first high-pressure tank (1) and the second high-pressure tank (2), and the path from the water storage device to the water inlets of the first high-pressure tank (1) and the second high-pressure tank (2); the transcritical carbon dioxide heat engine power generation unit is arranged on a path from the water outlets of the first high-pressure tank (1) and the second high-pressure tank (2) to the water storage device and is used for absorbing heat of the first high-pressure tank (1) and the second high-pressure tank (2) to generate power; the water outlets of the first high-pressure tank (1) and the second high-pressure tank (2) are respectively communicated with respective air inlets, and a circulating pump and a heater are arranged on pipelines from the water outlets of the first high-pressure tank (1) and the second high-pressure tank (2) to the respective air inlets along the flow direction of a medium; heat accumulators (14) are arranged on water inlet pipelines from the double-tank heat exchanger (15) to the first high-pressure tank (1) and the second high-pressure tank (2), the top of the first high-pressure tank (1) is communicated with a hot end inlet of the double-tank heat exchanger (15), a hot end outlet of the double-tank heat exchanger (15) is communicated with the top of the second high-pressure tank (2), and the first high-pressure tank (1) is communicated with a cold end outlet of the heat accumulator (14); the second high-pressure tank (2) is communicated with a cold end outlet of the heat accumulator (14); the hot end of the heat accumulator (14) is communicated with the output end of the medium-low temperature heat source.

2. The constant pressure pumped compressed air energy storage system with thermal storage of claim 1, wherein the medium and low temperature heat source is an industrial waste heat/waste heat, geothermal or solar thermal system.

3. The pumped compressed air energy storage system with thermal storage of constant pressure type of claim 1, characterized in that the double tank heat exchanger (15) is a heat pipe heat exchanger; the first high-pressure tank (1) and the second high-pressure tank (2) are identical in specification and made of high-temperature-resistant and corrosion-resistant materials, and the first high-pressure tank (1) and the second high-pressure tank (2) are wrapped by heat-insulating materials.

4. The pumped compressed air energy storage system with thermal storage of the constant pressure type of claim 1, wherein the transcritical carbon dioxide heat engine power generation unit comprises a carbon dioxide pump (18), a carbon dioxide heat exchanger (17), a carbon dioxide condenser (19) and a carbon dioxide turbine (20);

the outlet of the carbon dioxide pump (18) is communicated with the cold end inlet of the carbon dioxide heat exchanger (17) through a pipeline, the cold end outlet of the carbon dioxide heat exchanger (17) is communicated with the inlet of the carbon dioxide turbine (20), the outlet of the carbon dioxide turbine (20) is communicated with the hot end inlet of the carbon dioxide condenser (19) through a pipeline, the hot end outlet of the carbon dioxide condenser (19) is communicated with the inlet of the carbon dioxide pump (18) through a pipeline, a carbon dioxide circulating switch valve (25) is arranged between the hot end outlet of the carbon dioxide condenser (19) and the inlet of the carbon dioxide pump (18), and the carbon dioxide turbine (20).

5. The constant-pressure pumped compressed air energy storage system with heat storage function of claim 4, wherein the water outlets of the first high-pressure tank (1) and the second high-pressure tank (2) are respectively communicated with the hot end inlet of the carbon dioxide heat exchanger (17), and the hot end outlet of the carbon dioxide heat exchanger (17) is provided with a power generation and energy release expansion unit and a natural cold energy utilization device (22) along the medium flow direction; the water outlet of the power generation and energy release expansion unit is communicated with the water inlet of a natural cold energy utilization device (22), and the natural cold energy utilization device (22) comprises a cold energy absorption section, a heat recovery section and an intermediate energy storage section; the cold energy absorption section is used for absorbing external cold energy, the heat recovery section is used for absorbing heat of hot water, the middle energy storage section is used for storing the cold energy of the cold energy absorption section or the heat of the heat recovery section, and the middle energy storage section is arranged between the cold energy absorption section and the heat recovery section; the power generation and energy release expansion unit comprises a water turbine (21) and a generator, the water turbine is connected with the generator, and a water outlet of the water turbine (21) is communicated with a water inlet of the natural cold energy utilization device (22).

6. The pumped compressed air energy storage system with heat storage of the constant pressure type according to claim 5, wherein the intermediate energy storage section comprises a heat exchanger shell (27) and a phase change energy storage material (28), the heat exchanger shell (27) forms a closed space for accommodating the phase change energy storage material (28), the phase change energy storage material (28) is arranged in the heat exchanger shell (27), the heat exchanger shell (27) is externally wrapped by a heat insulating material, the cold energy absorption section comprises a condenser heat pipe (30), the heat recovery section comprises an evaporator heat pipe (31) and an evaporator shell (29), the evaporator shell (29) forms a circulating water circulation channel, the evaporation section of the evaporator heat pipe (31) is arranged in the evaporator shell (29), the condensation section of the evaporator heat pipe (31) is arranged in the heat exchanger shell (27), and the evaporator shell (29) is provided with a hot water inlet (32) and a cold water outlet (33), the hot water inlet (32) is communicated with the outlet of the water turbine (21); the cold water outlet (33) is communicated with a cold end inlet of a carbon dioxide condenser (19) in the transcritical carbon dioxide heat engine power generation unit, and a cold end outlet of the carbon dioxide condenser (19) is communicated with a water inlet of the water storage device (23).

7. The constant pressure pumped compressed air energy storage system with thermal storage of claim 6, wherein the evaporator heat pipes and the condenser heat pipes are gravity heat pipes arranged vertically; fins are arranged on the heat pipe.

8. The constant-pressure pumped compressed air energy storage system with heat storage function of claim 6, wherein the phase change energy storage material (28) is a solid-liquid phase change material with a phase change temperature of-15 to 20 ℃.

9. An operation method of a constant-pressure water pumping compressed air energy storage system with heat storage is characterized in that,

at the initial moment, air with set pressure is preset in the two high-pressure tanks, and the first energy storage/release process is as follows:

(1) in the energy storage stage, water flowing out of an outlet of the water storage device (23) is pressurized, then absorbs heat of gas flowing into the first high-pressure tank (1) from the second high-pressure tank (2) through the double-tank heat exchanger (15), absorbs heat of a medium-low temperature heat source through the heat accumulator (14), and enters the two high-pressure tanks after the temperature of the heat is further raised, so that the gas in the tanks is compressed, when the water level in the first high-pressure tank (1) is filled to a target position, water filling is stopped, water is continuously filled into the second high-pressure tank (2) until the second high-pressure tank (2) is filled with water, and at the moment, all gas in the high-pressure tank (2) enters the first high-pressure tank (1), and the energy storage process is completed;

(2) in the energy release stage, one part of water flowing out of the bottom of the first high-pressure tank (1) is cooled through a transcritical carbon dioxide heat engine power generation unit, and the other part of water is pumped into a heater through a circulating pump to be heated into superheated steam to enter the first high-pressure tank (1) for pressure supplement; simultaneously, water entering a transcritical carbon dioxide heat engine power generation unit heats supercritical carbon dioxide to generate power; when all water in the first high-pressure tank (2) flows out, a mixture of high-temperature air and water vapor coming out of the top of the first high-pressure tank (2) passes through the double-tank heat exchanger (15), the water vapor is completely condensed into liquid water, the low-temperature air and the liquid water enter the second high-pressure tank (1), the water in the second high-pressure tank (1) is pushed to flow out of the bottom of the tank body, and the water enters the water storage device (23) after being cooled by the transcritical carbon dioxide heat engine power generation unit until the water in the second high-pressure tank (1) completely flows out, so that the energy release process is completed;

the next energy storage/release process is as follows,

(1) in the energy storage stage, water flowing out of an outlet of the water storage device (23) is pressurized, then absorbs heat of gas flowing into the second high-pressure tank (2) from the first high-pressure tank (1) through the double-tank heat exchanger (15), absorbs heat of a medium-low temperature heat source through the heat accumulator (14), is further heated and then enters the two high-pressure tanks, gas in the tanks is compressed, and when the water level in the second high-pressure tank (2) is filled to a target position, water filling is stopped; continuously filling water into the first high-pressure tank (1) until the first high-pressure tank (1) is full of water, wherein in the process, a high-temperature water vapor and air mixture from the top of the first high-pressure tank passes through a double-tank heat exchanger (15), the water vapor is completely condensed into liquid water, the air and the liquid water enter the second high-pressure tank until all gas in the first high-pressure tank (1) enters the second high-pressure tank (2), and the energy storage process is finished;

(2) in the energy releasing stage, part of water flowing out of the bottom of the second high-pressure tank (2) is cooled through the transcritical carbon dioxide heat engine power generation unit, supercritical carbon dioxide in the transcritical carbon dioxide heat engine power generation unit is heated, so that the supercritical carbon dioxide does work to generate power and enters the water storage device (23) after being cooled, the other part of water is heated into superheated steam through the circulating pump and the heater to enter the second high-pressure tank (2) for supplementing pressure, after all the water in the second high-pressure tank (2) flows out, a mixture of high-temperature air and water vapor flowing out of the top of the second high-pressure tank (2) passes through the double-tank heat exchanger (15), the water vapor is completely condensed into liquid water, the low-temperature air and the liquid water enter the first high-pressure tank (1) to push the water in the first high-pressure tank (1) to flow out of the bottom of the tank, finishing the energy release process until the water in the first high-pressure tank (1) completely flows out;

the above two processes are alternately carried out, and repeated circulation is realized.

10. The method of claim 9, wherein the air of the set pressure is preset in both high pressure tanks at an initial time, and the initial energy release stage is: one part of water flowing out of the bottom of the first high-pressure tank (1) is cooled through a carbon dioxide heat exchanger (17), then work is output through a water turbine (21) to drive a power generation device G to generate power, the other part of water is pressurized through a circulating pump and then heated through a heater to form superheated steam, the superheated steam enters the first high-pressure tank (1) to supplement pressure, meanwhile, the water flowing out of the first high-pressure tank (1) heats supercritical carbon dioxide in the carbon dioxide heat exchanger (17), and the heated supercritical carbon dioxide enters a carbon dioxide turbine (20) to expand to work to drive the power generation device G to generate power; the water flowing out of the outlet of the water turbine (21) enters from a hot water inlet (32) of a heat recovery section of the natural cold utilization device (22), and the cold water flowing out of a cold water outlet (33) of the heat recovery section absorbs the heat of the carbon dioxide expanded by the carbon dioxide turbine (17) through a carbon dioxide condenser (19) and enters a water storage device (23); after all water in the first high-pressure tank (1) flows out, a mixture of high-temperature air and water vapor flowing out of the top of the first high-pressure tank (1) passes through the double-tank heat exchanger (15), the water vapor is completely condensed into liquid water, the liquid water and low-temperature air enter the second high-pressure tank (2), the water in the second high-pressure tank (2) is pushed to flow out of the bottom of the tank body, the temperature of the water is reduced through the carbon dioxide heat exchanger (17), then the water turbine (21) outputs work to drive the power generation device G to generate power, the water flowing out of the outlet of the water turbine (21) enters the natural cold energy utilization device (22) for heat recovery section to reduce the temperature, cold water flowing out of the cold water outlet (33) of the heat recovery section absorbs the carbon dioxide heat expanded by the carbon dioxide turbine (17) through the carbon dioxide condenser (19) and enters the water storage device (, completing the energy release process;

in the next energy releasing stage, part of water flowing out of the bottom of the second high-pressure tank (2) is cooled through a carbon dioxide heat exchanger (17), then power is output through a water turbine (21) to drive a power generation device to generate power, the other part of water is pressurized through a circulating pump, is heated into superheated steam through a heater and enters the second high-pressure tank (2) to supplement pressure, meanwhile, the water flowing out of the bottom of the second high-pressure tank (2) heats supercritical carbon dioxide through the carbon dioxide heat exchanger (17), and the heated supercritical carbon dioxide enters a carbon dioxide turbine (20) to expand to do power to drive the power generation device to generate power; after water flowing out of an outlet of a water turbine (21) enters a heat recovery section of a natural cold utilization device (22) for cooling, cold water flowing out of a cold water outlet (33) of the heat recovery section absorbs carbon dioxide heat expanded by a carbon dioxide turbine (17) through a carbon dioxide condenser (19) and enters a water storage device (23), after all water in a second high-pressure tank (2) flows out, a mixture of high-temperature air and water vapor flowing out of the top of the second high-pressure tank (2) passes through a double-tank heat exchanger (15), the water vapor is completely condensed into liquid water, the liquid water and low-temperature air enter a first high-pressure tank (1), water in the first high-pressure tank (1) is pushed to flow out of the bottom of the tank body and is cooled through the carbon dioxide heat exchanger (17), then the liquid turbine (21) outputs power to drive a power generation device for power generation, the water flowing out of an outlet of the water turbine (21) enters a heat, cold water flowing out of a cold water outlet (33) of the heat recovery section absorbs heat of carbon dioxide expanded by a carbon dioxide turbine (17) through a carbon dioxide condenser (19) and enters a water storage device (23), and after water in the first high-pressure tank (1) completely flows out, the energy release process is completed.

Technical Field

The invention relates to the technical field of physical energy storage, in particular to a constant-pressure water-pumping compressed air energy storage system with heat storage and an operation method.

Background

With the shortage of energy and the increasingly outstanding environmental problems, the vigorous development of renewable energy sources has attracted extensive attention. However, renewable energy sources such as wind energy and solar energy have randomness and volatility, and power generation by using the renewable energy sources and the renewable energy sources incorporated into a power grid can bring huge impact to the power grid, which also causes serious phenomena of wind abandon and light abandon in recent years. Energy storage technology is considered an important approach to effectively address this problem. The current mature large-scale energy storage technologies include a pumped-storage-technology (PHS) and a compressed-air energy storage technology (CAES), the pumped-storage-technology is greatly limited by geographical conditions, and the traditional compressed-air energy storage technology needs a large-volume air storage cave, so that the application of the two technologies is limited. The royal coruscation group provides a novel dam-free pumped storage technology, combines the traditional compressed air energy storage CAES with the PHS, tries to solve the defects of the existing CAES in principle, and breaks through the technical bottleneck restricting the popularization and application of the large-scale physical energy storage technology.

Generally, for an energy storage system, the pressure of stored high-pressure gas is continuously reduced along with the expansion process, so that the water turbine is always operated under variable working conditions, and the fluctuation of electric energy output is caused. Expansion at constant pressure may partially solve this problem. Previously, researchers have proposed methods of maintaining a constant pressure during the energy release process by adding water vapor. However, in the method, after the energy release process is finished, a mixture of air and water vapor with higher temperature and pressure exists in the tank, and if the mixture is not condensed and utilized, the next compression energy storage process is difficult to perform.

On the other hand, abundant natural night cooling capacity in areas with large day-night temperature difference is rarely utilized. According to the second law of thermodynamics, the temperature of the low-temperature heat source is reduced, and the circulation efficiency of the system can be effectively improved. If the night cold is collected and collected to be applied to the low-temperature heat source end of the heat circulation system in a large scale, the energy utilization efficiency is better.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a method for operating a constant-pressure water-pumping compressed air energy storage system with heat storage, and the continuous work of the constant-pressure water-pumping compressed air energy storage system adopting steam for pressure compensation is realized.

In order to achieve the purpose, the invention adopts the technical scheme that: a constant-pressure water pumping compressed air energy storage system with heat storage comprises a first high-pressure tank, a second high-pressure tank, a double-tank heat exchanger and a trans-critical carbon dioxide heat engine power generation unit, wherein water inlets and water outlets of the first high-pressure tank and the second high-pressure tank are respectively communicated with a water storage device, air inlets and air outlets of the first high-pressure tank and the second high-pressure tank are mutually communicated, the double-tank heat exchanger is arranged on a path communicated with the air inlets and the air outlets of the first high-pressure tank and the second high-pressure tank, and the path from the water storage device to the water inlets of the first high-pressure tank and the second high-; the transcritical carbon dioxide heat engine power generation unit is arranged on a path from the water outlets of the first high-pressure tank and the second high-pressure tank to the water storage device and is used for absorbing heat of the first high-pressure tank and the second high-pressure tank to generate power; the water outlets of the first high-pressure tank and the second high-pressure tank are respectively communicated with respective air inlets, and a circulating pump and a heater are arranged on pipelines from the water outlets of the first high-pressure tank and the second high-pressure tank to the respective air inlets along the medium flow direction; the pipeline from the double-tank heat exchanger to the water inlets of the first high-pressure tank and the second high-pressure tank is provided with a heat accumulator, the top of the first high-pressure tank is communicated with the hot end inlet of the double-tank heat exchanger, the hot end outlet of the double-tank heat exchanger is communicated with the top of the second high-pressure tank, and the first high-pressure tank is communicated with the cold end outlet of the heat accumulator; the second high-pressure tank is communicated with a cold end outlet of the heat accumulator; the hot end of the heat accumulator is communicated with the output end of the medium-low temperature heat source.

The medium-low temperature heat source is an industrial waste heat/waste heat, geothermal or solar heat system.

The double-tank heat exchanger adopts a heat pipe heat exchanger; the first high-pressure tank and the second high-pressure tank are identical in specification and made of high-temperature-resistant and corrosion-resistant materials, and the first high-pressure tank and the second high-pressure tank are wrapped by heat-insulating materials.

The transcritical carbon dioxide heat engine power generation unit comprises a carbon dioxide pump, a carbon dioxide heat exchanger, a carbon dioxide condenser and a carbon dioxide turbine;

the carbon dioxide pump export is through pipeline and carbon dioxide heat exchanger cold junction import intercommunication, the cold junction export of carbon dioxide heat exchanger and the import intercommunication of carbon dioxide turbine, the export of carbon dioxide turbine is through pipeline and carbon dioxide condenser hot end import intercommunication, carbon dioxide condenser hot end export is through pipeline and carbon dioxide pump's import intercommunication, set up carbon dioxide circulation switch valve between carbon dioxide condenser hot end export and the import of carbon dioxide pump, the carbon dioxide turbine is connected with the generator.

The water outlets of the first high-pressure tank and the second high-pressure tank are respectively communicated with a hot end inlet of a carbon dioxide heat exchanger, and a power generation and energy release expansion unit and a natural cold energy utilization device are arranged at a hot end outlet of the carbon dioxide heat exchanger along the medium flow direction; the water outlet of the power generation and energy release expansion unit is communicated with the water inlet of the natural cold energy utilization device, and the natural cold energy utilization device comprises a cold energy absorption section, a heat energy recovery section and an intermediate energy storage section; the cold energy absorption section is used for absorbing external cold energy, the heat recovery section is used for absorbing heat of hot water, the middle energy storage section is used for storing the cold energy of the cold energy absorption section or the heat of the heat recovery section, and the middle energy storage section is arranged between the cold energy absorption section and the heat recovery section; the power generation and energy release expansion unit comprises a water turbine and a generator, the water turbine is connected with the generator, and a water outlet of the water turbine is communicated with a water inlet of the natural cold energy utilization device.

The intermediate energy storage section comprises a heat exchanger shell and a phase-change energy storage material, the heat exchanger shell forms a closed space for containing the phase-change energy storage material, the phase-change energy storage material is arranged in the heat exchanger shell, the exterior of the heat exchanger shell is wrapped by a heat insulating material, the cold energy absorption section comprises a condenser heat pipe, the heat recovery section comprises an evaporator heat pipe and an evaporator shell, the evaporator shell forms a circulating water circulation channel, the evaporation section of the evaporator heat pipe is arranged in the evaporator shell, the condensation section of the evaporator heat pipe is arranged in the heat exchanger shell, the evaporator shell is provided with a hot water inlet and a cold water outlet, and the hot water inlet is communicated with the outlet of; the cold water outlet is communicated with the cold end inlet of a carbon dioxide condenser in the transcritical carbon dioxide heat engine power generation unit, and the cold end outlet of the carbon dioxide condenser is communicated with the water inlet of the water storage device.

The evaporator heat pipe and the condenser heat pipe are gravity type heat pipes and are vertically arranged; fins are arranged on the heat pipe.

The phase change energy storage material is a solid-liquid phase change material with the phase change temperature of-15-20 ℃.

The invention also provides an operation method of the constant-pressure water pumping compressed air energy storage system with heat storage,

at the initial moment, air with set pressure is preset in the two high-pressure tanks, and the first energy storage/release process is as follows:

(1) in the energy storage stage, water flowing out of an outlet of the water storage device is pressurized, then is absorbed by the double-tank heat exchanger, and flows into the first high-pressure tank from the second high-pressure tank, the heat of the medium-low temperature heat source is absorbed by the heat accumulator, the temperature of the water is further raised, the water enters the two high-pressure tanks, so that the gas in the tanks is compressed, when the water level in the first high-pressure tank is filled to a target position, the water filling is stopped, the water is continuously filled into the second high-pressure tank until the second high-pressure tank is filled with water, and at the moment, all the gas in the high-pressure tanks enters the first high-pressure;

(2) in the energy release stage, part of water flowing out of the bottom of the first high-pressure tank is cooled through a transcritical carbon dioxide heat engine power generation unit, and the other part of water is pumped into a heater through a circulating pump to be heated into superheated steam to enter the first high-pressure tank for supplementing pressure; simultaneously, water entering a transcritical carbon dioxide heat engine power generation unit heats supercritical carbon dioxide to generate power; after all the water in the first high-pressure tank flows out, the mixture of high-temperature air and water vapor coming out of the top of the first high-pressure tank passes through a double-tank heat exchanger, the water vapor is completely condensed into liquid water, the low-temperature air and the liquid water enter a second high-pressure tank, the water in the second high-pressure tank is pushed to flow out from the bottom of the tank body, and after the temperature of the water is reduced by a transcritical carbon dioxide heat engine power generation unit, the water enters a water storage device until the water in the second high-pressure tank completely flows out, the energy release process is completed;

the next energy storage/release process is as follows,

(1) in the energy storage stage, water flowing out of an outlet of the water storage device is pressurized, then absorbs heat of gas flowing into the second high-pressure tank from the first high-pressure tank through the double-tank heat exchanger, absorbs heat of the medium-low temperature heat source through the heat accumulator, further raises the temperature, enters the two high-pressure tanks, compresses the gas in the tanks, and stops filling water when the water level in the second high-pressure tank is filled to a target position; continuously filling water into the first high-pressure tank until the first high-pressure tank is full of water, wherein in the process, a high-temperature water vapor and air mixture from the top of the first high-pressure tank passes through the double-tank heat exchanger, the water vapor is completely condensed into liquid water, and the low-temperature air and the liquid water enter the second high-pressure tank until all gas in the first high-pressure tank enters the second high-pressure tank, so that the energy storage process is finished;

(2) in the energy releasing stage, part of water flowing out of the bottom of the second high-pressure tank is cooled through the transcritical carbon dioxide heat engine power generation unit to heat the supercritical carbon dioxide in the transcritical carbon dioxide heat engine power generation unit, so that the supercritical carbon dioxide does work to generate power, the cooled water enters the water storage device, the other part of the water is heated into superheated steam through the circulating pump and the heater and enters the second high-pressure tank to supplement the pressure, after all the water in the second high-pressure tank flows out, the mixture of high-temperature air and water vapor coming out from the top of the second high-pressure tank passes through the double-tank heat exchanger, the water vapor is completely condensed into liquid water, the low-temperature air and the liquid water enter the first high-pressure tank, the water in the first high-pressure tank is pushed to flow out from the bottom of the tank body, after the temperature is reduced by the transcritical carbon dioxide heat engine power generation unit, the water enters the water storage device until the water in the first high-pressure tank completely flows out, and the energy release process is completed;

the above two processes are alternately carried out, and repeated circulation is realized.

The two high-pressure tanks are pre-provided with air with set pressure at the initial moment, and the initial energy release stage is as follows: one part of water flowing out of the bottom of the first high-pressure tank is cooled through a carbon dioxide heat exchanger, then the water passes through a water turbine to output work to drive a power generation device G to generate power, the other part of the water passes through a circulating pump to be pressurized, then the water is heated into superheated steam through a heater to enter the first high-pressure tank to supplement pressure, meanwhile, the water flowing out of the first high-pressure tank heats supercritical carbon dioxide in the carbon dioxide heat exchanger, and the heated supercritical carbon dioxide enters a carbon dioxide turbine to expand to do work to drive the power generation device; the water flowing out of the outlet of the water turbine enters from a hot water inlet of a heat recovery section of the natural cold energy utilization device, and the cold water flowing out of a cold water outlet of the heat recovery section absorbs the heat of the carbon dioxide expanded by a carbon dioxide turbine through a carbon dioxide condenser and enters a water storage device; after all the water in the first high-pressure tank flows out, a mixture of high-temperature air and water vapor flowing out of the top of the first high-pressure tank passes through a double-tank heat exchanger, the water vapor is completely condensed into liquid water, the liquid water and low-temperature air enter a second high-pressure tank, the water in the second high-pressure tank is pushed to flow out of the bottom of the tank body, the temperature of the water is reduced through a carbon dioxide heat exchanger, then the water passes through a water turbine to output power to drive a power generation device G to generate power, the water flowing out of an outlet of the water turbine enters a natural cold energy utilization device heat recovery section to be reduced, cold water flowing out of a cold water outlet of a heat recovery section absorbs carbon dioxide heat expanded by a carbon dioxide turbine through a carbon dioxide condenser and enters a;

in the next energy releasing stage, part of water flowing out of the bottom of the second high-pressure tank is cooled through a carbon dioxide heat exchanger, then is output by a water turbine to drive a power generation device to generate power, the other part of water is pressurized through a circulating pump, is heated into superheated steam through a heater and enters the second high-pressure tank to supplement pressure, meanwhile, the water flowing out of the bottom of the second high-pressure tank heats supercritical carbon dioxide through the carbon dioxide heat exchanger, and the heated supercritical carbon dioxide enters a carbon dioxide turbine to expand and do work to drive the power generation device to generate power; after water flowing out of an outlet of the water turbine enters a heat recovery section of the natural cold utilization device for cooling, cold water flowing out of a cold water outlet of the heat recovery section absorbs carbon dioxide heat expanded by a carbon dioxide turbine through a carbon dioxide condenser, the cold water enters a water storage device, after all water in the second high-pressure tank flows out, a high-temperature air and water vapor mixture flowing out of the top of the second high-pressure tank passes through a double-tank heat exchanger, the water vapor is completely condensed into liquid water, the liquid water and low-temperature air enter a first high-pressure tank, the water in the first high-pressure tank is pushed to flow out from the bottom of a tank body, the temperature is reduced through the carbon dioxide heat exchanger, then a power generation device is driven to generate power through the output power of the water turbine, the water flowing out of an outlet of the water turbine enters a heat recovery section of the natural cold utilization device for cooling, and (4) entering a water storage device, and finishing the energy release process after the water in the first high-pressure tank completely flows out.

Compared with the prior art, the invention has at least the following beneficial effects: the invention adopts a double-tank structure and aims at the double-tank structure to arrange the circulating pump and the heating device, thereby effectively solving the problem that the tank is difficult to compress in the next energy storage process due to high-temperature air and water vapor after the pressure is supplemented by water vapor, and realizing the repeated circulating work of the constant-pressure water pumping compression energy storage system adopting the water vapor for supplementing pressure;

the storage and utilization of medium and low temperature heat energy are increased on the basis of the original storage pressure potential energy, and the energy storage density is improved;

the invention does not need afterburning and pollution-free, and meanwhile, when the heater in the double-tank structure can also adopt a solar heating mode to replace an electric heating mode to heat water into superheated steam for pressure compensation, the efficiency of the system can be greatly improved;

the temperature of the stored hot water can be changed according to the pressure of the stored air, and when the stored pressure is higher, the temperature of the stored hot water can be increased; the storable hot water temperature may also be increased, and the corresponding efficiency of the transcritical carbon dioxide cycle system may also be increased.

Furthermore, the heat exchanger in the double-tank structure adopts a heat pipe heat exchanger, so that the volume of the heat exchanger is greatly reduced, the heat exchange efficiency is improved, meanwhile, the heat exchange temperature difference of cold and hot fluids can be reduced, and the heat exchange temperature difference change caused by the change of the cold and hot fluid clockwise/counter-current arrangement mode in the heat exchanger is avoided;

further, the medium and low temperature heat sources with volatility, such as industrial waste heat/waste heat, geothermal heat, solar energy and the like, are stored, so that the stable output of heat energy is realized;

furthermore, the invention stores the natural cold energy at night for condensing the carbon dioxide which does work, and compared with the conventional cooling water, the invention can reduce the condensing temperature and improve the system efficiency of the transcritical carbon dioxide circulation.

Furthermore, the natural cold energy utilization device adopts a gravity type heat pipe heat exchanger, and fins are uniformly distributed on the heat pipe, so that the heat exchange energy is further increased.

Furthermore, the direction of the high-temperature water flow flowing into the carbon dioxide heat exchanger through the high-pressure tank is opposite to the direction of the carbon dioxide flowing into the cold end inlet of the carbon dioxide heat exchanger, and the direction of the water flow flowing into the carbon dioxide condenser through the cold water outlet of the natural cold utilization unit is opposite to the direction of the carbon dioxide flowing into the hot end inlet of the carbon dioxide condenser.

Drawings

FIG. 1 is a schematic diagram of a constant pressure pumped compressed air energy storage system with heat storage according to an embodiment of the present invention

FIG. 2 is a schematic view of the natural cold utilizing apparatus according to the embodiment of the present invention

In the figure: 1 a first high-pressure tank, 2 a second high-pressure tank, 3 a second circulating pump, 4 a second heater, 5 a first circulating pump, 6 a second heater, 7 a first circulating switch valve, 8 a first switch valve, 9 a second communication valve, 10 a second switch valve, 11 a second water inlet valve, 12 a first water inlet valve, 13 a second circulating switch valve, 14 a heat accumulator, 15 a double-tank heat exchanger, 16 a water outlet valve, 17 a carbon dioxide heat exchanger, 18 a carbon dioxide pump, 19 a carbon dioxide condenser, 20 a carbon dioxide turbine, 21 a water turbine, 22 a natural cold energy utilization device, 23 a water storage device, 24 a first communication valve, 25 a carbon dioxide circulating switch valve, 26 a water supply pump, 27-heat exchanger shells 27, 28-phase change energy storage materials, 29-evaporator shells, 30-condenser heat pipes, 31-evaporator heat pipes, 32-hot water inlets 33-cold water outlets.

Detailed Description

The present invention will now be described in further detail with reference to specific examples, which are intended to be illustrative, but not limiting, of the invention.

Referring to fig. 1, the constant-pressure pumped compressed air energy storage system with heat storage comprises a transcritical carbon dioxide heat engine power generation unit, a natural cold utilization unit, a medium-low temperature heat source supply unit, a double-tank structure for storing and storing air and an expansion unit for connecting a power generator to release energy. The double-tank structure for storing gas and heat is used for storing heat absorbed by a low-temperature heat source, heat provided by the heat exchanger and compressed air potential energy; the transcritical carbon dioxide heat engine power generation unit is used for absorbing heat provided by the double-tank structure to generate power; the natural cold energy utilization unit is used for storing natural cold energy at night to cool the water flow at the outlet of the water turbine; the medium-low temperature heat source supply unit is used for supplying a heat source to the transcritical carbon dioxide heat engine power generation unit; the expansion unit is used for being connected with the generator to release energy and is used for generating power by the pressure potential energy stored in the double-tank structure.

The double-tank structure for gas storage and heat storage comprises a first high-pressure tank 1, a second high-pressure tank 2, a first communicating valve 24, a double-tank heat exchanger 15, a first heater 6, a second heater 4, a second circulating pump 3, a first circulating pump 5, a first circulating switch valve 7, a second circulating switch valve 13, a first switch valve 8, a first water inlet valve 12, a second switch valve 10 and a second water inlet valve 11;

1 top of first high-pressure tank is through pipeline through first intercommunication valve 24 and 15 hot end imports of double-tank heat exchanger, and the export of 15 hot ends of double-tank heat exchanger is through pipeline and 2 tops of second high-pressure tank intercommunication, two branches of 1 bottom of first high-pressure tank, a branch road: the bottom of the first high-pressure tank 1 is communicated with the inlet of a first circulating pump 5 through a pipeline via a first circulating switch valve 7, the outlet of the first circulating pump 5 is communicated with the inlet of a first heater 6 through a pipeline, and the outlet of the first heater 6 is communicated with the top of the first high-pressure tank 1 through a pipeline. The other branch circuit: the first high-pressure tank 1 is communicated with a hot end inlet of a carbon dioxide heat exchanger 17 through a first switch valve 8 and a water outlet valve 16 by pipelines or communicated with a cold end outlet of a heat accumulator 14 through the first switch valve 8 and a first water inlet valve 12 by pipelines.

Two branches at the bottom of second high-pressure tank 2, one branch: the bottom of the second high-pressure tank 2 is communicated with the inlet of a second circulating pump 3 through a second circulating switch valve 13 by a pipeline, the outlet of the second circulating pump 3 is communicated with the inlet of a second heater 4 by a pipeline, and the outlet of the second heater 4 is communicated with the top of the second high-pressure tank 2 by a pipeline. The other branch circuit: the second high-pressure tank 2 is communicated with a hot end inlet of a carbon dioxide heat exchanger 17 through a second water inlet valve 10, a second communication valve 9 and a water outlet valve 16 through pipelines or is communicated with a cold end outlet of a heat accumulator 14 through a second switch valve 10 and a second water inlet valve 11 through pipelines.

The transcritical carbon dioxide heat engine power generation unit comprises a carbon dioxide pump 18, a carbon dioxide heat exchanger 17, a carbon dioxide condenser 19, a carbon dioxide turbine 20 and a carbon dioxide circulating switch valve 25. In the transcritical carbon dioxide heat engine power generation unit, the outlet of a carbon dioxide pump 18 is communicated with the inlet of the cold end of a carbon dioxide heat exchanger 17 through a pipeline, the outlet of the cold end of the carbon dioxide heat exchanger is communicated with the inlet of a carbon dioxide turbine 20, the outlet of the carbon dioxide turbine is communicated with the inlet of the hot end of a carbon dioxide condenser 19 through a pipeline, and the outlet of the hot end of the carbon dioxide condenser 19 is communicated with the inlet of the carbon dioxide pump 18 through a carbon dioxide.

The medium-low temperature heat source utilization unit comprises a heat accumulator 14, the hot end of the heat accumulator 14 is communicated with the output end of the medium-low temperature heat source, the outlet of the cold end of the heat accumulator 14 is communicated with the double-tank structure through a pipeline, and the inlet of the cold end of the heat accumulator 14 is communicated with the outlet of the cold end of the double-tank heat exchanger 15 through a pipeline; the low-temperature heat source is an industrial waste heat/waste heat, geothermal or solar thermal system.

Referring to fig. 2, the cold source of the natural cold utilization device is the cold in the night environment, the natural cold utilization device includes a cold absorption section, a heat recovery section, and an intermediate energy storage section, the intermediate energy storage section includes a heat exchanger shell 27 and a phase change energy storage material 28, the heat exchanger shell 27 forms an enclosed space for accommodating the phase change energy storage material 28, the phase change energy storage material 28 is disposed in the heat exchanger shell 27, the cold absorption section includes a condenser heat pipe 30, the heat recovery section includes an evaporator heat pipe 31 and an evaporator shell 29, the evaporator shell 29 forms a circulating water circulation channel, a first section of the evaporator heat pipe 31 is disposed in the evaporator shell 29, a second section of the evaporator heat pipe 31 is disposed in the heat exchanger shell 27, and the evaporator shell 29 is provided with a hot water inlet 32 and a cold water outlet 33.

The cold energy absorption section is positioned above the middle energy storage section, and the heat recovery section is positioned below the middle energy storage section; the outer wall of the heat exchanger shell 27 is provided with a heat insulating layer, the heat exchanger shell 27 is filled with a phase change energy storage material 28, and the heat exchanger shell 27 and an evaporator shell 29 are connected into a whole; the evaporation end of the condenser heat pipe 30 is positioned in the phase change energy storage material of the middle energy storage section, and the condensation end of the condenser heat pipe 30 is exposed in the external environment; the evaporator shell 29 is provided with a hot water inlet 32 and a cold water outlet 33, the hot water inlet 32 is communicated with the outlet of the water turbine 21 through a pipeline, and the cold water outlet 33 is communicated with the cold end inlet of the carbon dioxide condenser 19 through a pipeline; the condensation end of the evaporator heat pipe 31 is positioned in the phase change energy storage material of the middle energy storage section, and the evaporation end of the evaporator heat pipe 31 is positioned in the evaporator shell.

The evaporator heat pipe 31 and the condenser heat pipe 30 are both gravity type heat pipes and are vertically arranged; fins are uniformly distributed on the gravity type heat pipe, and the number of the fins is adjusted according to the actual heat exchange condition.

The expansion unit used for connecting the generator to release energy comprises a water turbine 21 and a generator G, wherein the inlet of the water turbine 21 is communicated with the hot end outlet of the carbon dioxide heat exchanger 17 through a pipeline, and the outlet of the water turbine 21 is communicated with the hot water inlet 32 of the evaporator shell 29 of the natural cold utilization device through a pipeline.

In the daytime, hot water flowing out of the outlet of the water turbine 21 enters from the hot water inlet of the evaporator shell, the evaporation section of the evaporator heat pipe 31 absorbs heat and transfers the heat to the condensation section of the evaporator heat pipe, the heat is transferred to the phase change energy storage material 28 in the middle energy storage section from the condensation section of the evaporator heat pipe 31, the phase change energy storage material 28 is changed from a solid state to a liquid state, and the hot water heat is recovered in the middle energy storage section; the hot water turns into cold water and flows out from a cold water outlet 33 of the evaporator shell to a cold end inlet of the carbon dioxide condenser 19; when the ambient temperature is lower at night, the evaporation section of the condenser heat pipe 30 transfers the heat stored in the phase change energy storage material 28 of the middle energy storage section to the condensation section of the condenser heat pipe 30, the heat is transferred to the environment from the condensation section of the condenser heat pipe 30, the phase change energy storage material 28 is changed from a liquid state to a solid state, and the natural cold is stored in the middle energy storage section.

The inlet of the water turbine is communicated with the outlet of the hot end of the carbon dioxide heat exchanger through a pipeline, and the outlet of the water turbine is communicated with the hot water inlet end of the evaporation section shell of the natural cold utilization device.

As an alternative embodiment:

at the initial moment, air with set pressure is preset in the two high-pressure tanks, and the first energy storage/release process is as follows:

(1) in the energy storage stage, water flowing out of an outlet of the water storage device 23 is pressurized, then the heat of gas flowing into the first high-pressure tank 1 from the second high-pressure tank 2 is absorbed by the double-tank heat exchanger 15, the gas is further heated by the heat of the medium-low temperature heat source absorbed by the heat accumulator 14, the gas enters the two high-pressure tanks, the gas in the tanks is compressed, when the water level in the first high-pressure tank 1 is filled to a target position, the water filling is stopped, the water is continuously filled into the second high-pressure tank 2 until the second high-pressure tank 2 is filled with the water, and at the moment, all the gas in the high-pressure tank 2 enters the first high-pressure tank 1, so;

(2) in the energy release stage, one part of water flowing out of the bottom of the first high-pressure tank 1 is cooled through a transcritical carbon dioxide heat engine power generation unit, and the other part of water is pumped into a heater through a circulating pump to be heated into superheated steam to enter the first high-pressure tank 1 for pressure supplement; simultaneously, water entering a transcritical carbon dioxide heat engine power generation unit heats supercritical carbon dioxide to generate power; when all the water in the first high-pressure tank 2 flows out, the mixture of high-temperature air and water vapor coming out from the top of the first high-pressure tank 2 passes through the double-tank heat exchanger 15, the water vapor is completely condensed into liquid water, the low-temperature air and the liquid water enter the second high-pressure tank 1, the water in the second high-pressure tank 1 is pushed to flow out from the bottom of the tank body, and the water enters the water storage device 23 after being cooled by the transcritical carbon dioxide heat engine power generation unit until the water in the second high-pressure tank 1 completely flows out, and the energy release process is completed;

the next energy storage/release process is as follows,

(1) in the energy storage stage, water flowing out of an outlet of the water storage device 23 is pressurized, then absorbs heat of gas flowing into the second high-pressure tank 2 from the first high-pressure tank 1 through the double-tank heat exchanger 15, absorbs heat of a medium-low temperature heat source through the heat accumulator 14, further raises the temperature, enters the two high-pressure tanks, compresses gas in the tanks, and stops filling water when the water level in the second high-pressure tank 2 is filled to a target position; continuing to fill water into the first high-pressure tank 1 until the first high-pressure tank 1 is filled with water, wherein in the process, a high-temperature water vapor and air mixture from the top of the first high-pressure tank passes through the double-tank heat exchanger 15, the water vapor is completely condensed into liquid water, and the air and the liquid water enter the second high-pressure tank until all gas in the first high-pressure tank 1 enters the second high-pressure tank 2, so that the energy storage process is completed;

(2) in the energy releasing stage, part of water flowing out of the bottom of the second high-pressure tank 2 is cooled through the transcritical carbon dioxide heat engine power generation unit to heat the supercritical carbon dioxide in the transcritical carbon dioxide heat engine power generation unit, so that the supercritical carbon dioxide does work to generate power, the cooled water enters the water storage device 23, the other part of water is heated into superheated steam through the circulating pump and the heater to enter the second high-pressure tank 2 to supplement pressure, when all the water in the second high-pressure tank 2 flows out, a high-temperature air and water vapor mixture flowing out of the top of the second high-pressure tank 2 passes through the double-tank heat exchanger 15, the water vapor is completely condensed into liquid water, the low-temperature air and the liquid water enter the first high-pressure tank 1 to push the water in the first high-pressure tank 1 to flow out of the bottom of the tank body, the cooled water enters the water storage device 23 after passing through, completing the energy release process;

the above two processes are alternately carried out, and repeated circulation is realized.

As another embodiment, the operation method of the constant-pressure pumped compressed air energy storage system with heat storage of the present invention includes a first energy storage stage, a first energy release stage, a second energy storage stage, and a second energy release stage:

(1) at the initial moment, air with set pressure is preset in the two high-pressure tanks, and the first energy storage/release process is as follows:

the two high-pressure tanks are pre-provided with air with set pressure at the initial moment, and the initial energy release stage is as follows: one part of water flowing out of the bottom of the first high-pressure tank 1 is cooled through a carbon dioxide heat exchanger 17, then work is output through a water turbine 21 to drive a power generation device G to generate power, the other part of water is pressurized through a circulating pump and is heated into superheated steam through a heater to enter the first high-pressure tank 1 to supplement pressure, meanwhile, the water flowing out of the first high-pressure tank 1 heats supercritical carbon dioxide in the carbon dioxide heat exchanger 17, and the heated supercritical carbon dioxide enters a carbon dioxide turbine 20 to expand to do work to drive the power generation device G to generate power; the water flowing out of the outlet of the water turbine 21 enters from a hot water inlet 32 of a heat recovery section of the natural cold utilization device 22, and the cold water flowing out of a cold water outlet 33 of the heat recovery section absorbs the heat of the carbon dioxide expanded by the carbon dioxide turbine 17 through a carbon dioxide condenser 19 and enters a water storage device 23; after all the water in the first high-pressure tank 1 flows out, a mixture of high-temperature air and water vapor flowing out of the top of the first high-pressure tank 1 passes through the double-tank heat exchanger 15, the water vapor is completely condensed into liquid water, the liquid water and low-temperature air enter the second high-pressure tank 2 to push the water in the second high-pressure tank 2 to flow out of the bottom of the tank body, the water is cooled through the carbon dioxide heat exchanger 17, then the water is output through the water turbine 21 to drive the generating set G to generate electricity, the water flowing out of the outlet of the water turbine 21 enters the natural cold energy utilization device 22 heat recovery section to be cooled, the cold water flowing out of the cold water outlet 33 of the heat recovery section absorbs the carbon dioxide heat expanded by the carbon dioxide turbine 17 through the carbon dioxide condenser 19 and enters the water storage device 23, and the;

(2) in the second energy storage/second energy release stage, part of water flowing out of the bottom of the second high-pressure tank 2 is cooled through the carbon dioxide heat exchanger 17, then the water passes through the water turbine 21 to output work to drive the power generation device to generate power, the other part of water is pressurized through the circulating pump, the water is heated into superheated steam through the heater to enter the second high-pressure tank 2 to supplement pressure, meanwhile, the water flowing out of the bottom of the second high-pressure tank 2 passes through the carbon dioxide heat exchanger 17 to heat supercritical carbon dioxide, and the heated supercritical carbon dioxide enters the carbon dioxide turbine 20 to expand and do work to drive the power generation device; after the water flowing out of the outlet of the water turbine 21 enters the heat recovery section of the natural cold utilization device 22 for cooling, the cold water flowing out of the cold water outlet 33 of the heat recovery section absorbs the heat of the carbon dioxide expanded by the carbon dioxide turbine 17 through the carbon dioxide condenser 19 and enters the water storage device 23, after all the water in the second high-pressure tank 2 flows out, the mixture of high-temperature air and water vapor flowing out of the top of the second high-pressure tank 2 passes through the double-tank heat exchanger 15, the water vapor is completely condensed into liquid water, the liquid water and the low-temperature air enter the first high-pressure tank 1 to push the water in the first high-pressure tank 1 to flow out of the bottom of the tank body, the water is cooled through the carbon dioxide heat exchanger 17 and then passes through the water turbine 21 to output work to drive the power generation device to generate power, the water flowing out of the outlet of the water turbine 21 enters the heat recovery section of the natural cold utilization device 22 And the water enters the water storage device 23, and the energy release process is completed after the water in the first high-pressure tank 1 completely flows out.

The above two processes are alternately carried out, and repeated circulation is realized.